Automatic traffic signal



Dec. 31, 1940. T. o. WOHLSEN AUTOMATIC TRAFFIC SIGNAL 2 Sheets-Sheet 1 Filed July 22, 1958 h z w 6 a 7 a All Alll m 7 1 T. o. WOHLSEN 2,227,332 AUTOMATIC TRAFFIC SIGNAL Filed July 22; 1958 2 Sheets-Sheet 2 Patented Dec. 31, 1940 UNITED STATES PATENT OFFICE Claims.

My invention relates to an improvement in automatic traffic signals.

It is the expressed intention of my invention to overcome one of the main faults of the so- 5 called bulls-eye type of traffic signal which is in common use, namely the very poor visibility afforded the driver on arriving at an intersection on the opposite side of the street from the trailic signal location, and especially under certain conditions of sunlight. It is common knowledge in various cities and towns that, at many intersections, it is impossible to determine the color of the signal from certain positions at the intersection where it is, nevertheless, permissible to drive. It is my belief that with this signal it will be possible to control traffic at the intersection of two one-way streets with a single trafiic signal,

and, to accomplish this, means is employed which make it impossible for the driver on one intersecting street to see the signals controlling traffic on the other intersecting street, and vice versa,

and the design of lenses and reflectors is such that a portion of the light of the lamp employed is reflected directly perpendicular to the lens at all points, and, therefore, in direct line with the line of vision of the driver, thus insuring equal visibility from all angles within the arc to which the signal is limited. This improvement is equally applicable if two of the signals, instead of one, are employed to control traffic at two intersecting two-way streets.

Contributory to this invention, the following may be mentioned, to wit: The design of the refiectors; the design of the lenses; the mechanical use of a vane or similar device in connection with the equal visibility type of signal device; if desirable, a telescopic arrangement of vane; and,

finally, the combination of all the factors which make equal visibility possible.

In the accompanying drawings:

Fig. 1 is a view in perspective of the proposed signal;

Fig. 2 is a diagram of a one-way street intersection;

Fig. 3 is a horizontal section on line 3--3 of Fig. 4;

Fig. 4 is a view of one of the sides;

Fig. 5 is a vertical cross-section through the telescopic part of one of the vanes on the line 55 of Fig. 3.

A represents the signal mounted on a post I. The main part of the signal consists preferably of a pressed steel casing, the front side 2 of which is in the form of a circular arc of, say, slightly more than one-quarter of the circumference of a circle.

In this curved side of the casing, curved lenses 3 to I are mounted. These lenses are of the various colors required, as for instance red, amber and green, in reverse order as shown in Fig. 1, andcolored straight lenses 8 and 9 are mounted in the straight sides l0 and H of the signal.

Within the casing there are three separate compartments l2, placed one above the other, and corresponding to the three different signal lights, and each compartment 12 is provided with a lamp l3 and reflectors I4 preferably of special design. These compartments will be lined top and bottom with a reflecting surface, and para bolic reflectors as indicated in the horizontal section, Fig. 3, would extend perpendicularly from top to bottom of each compartment.

A sun-shield l5, as indicated by dotted lines in Fig. 3, may or may not be used as required, and its purpose is to shade the lenses from sun light, and it might be built integrally with the casing.

Vanes are hinged vertically at the front center of the curved side of the casing, as indicated by the pivot 16. termined to some extent by the width of the streets at any intersection where the signal might be used, and since only the two long perpendicular sides are required for the purpose of the device, it would be possible and probably advisable to make these vanes telescopic, and composed of two sections I1 and 18, as indicated, to facilitate adjustment of the vanes of the signal to various conditions.

Means for adjusting the angle of these vanes is provided by the slotted straps 20, and the bolt 2!. This stud bolt 2| passes through the slots of the straps 2!] as shown in Figs. 1, 3 and 4 to provide means to adjust the angle of the vanes with respect to each other, and the nut on the bolt permits this adjustment. The vanes themselves are hinged independently to the front of the casing, and the friction between the telescopic sections of the vanes holds them at the desired predetermined length.

The lenses 8 and 9 on the straight side, as shown in Figs. 1 and 3 are the pedestrian lenses, and they are lighted through an opening 22 from the electric lamp I3.

This signal system is applicable to two-way traffic as well as one-way traffic, and for twoway traffic another signal would be located diagrammatically opposite the one shown in the diagram of traffic shown in Fig. 2. The driver of car X headed east is prevented from seeing the Since the size of the vane is dewhen that is green, it is his signal to go, and of course it is understood when green shows on one side of the vanes, red shows on the other side.

To recapitulate, this signal consists of lamps, lenses and reflectors, the lenses and reflectors being so shaped and so placed in relation to each other that the signal light is directed perpendicular to the plane of the lens at the point where it passes through the lens, so as to result in a minimum of diffusion of the light and directly in the line of vision of the driver located at any point across the width of a given street, so that maximum visibility results. In addition to the above basic principle, my improved signal also provides an adjustable vane, so designed that the signal for one street is fully visible to the driver on that street, while the signal for the intersecting street is invisible to these same drivers. The invention further provides by means of an aperture 22 in the back of the main reflector, and by means of auxiliary reflectors and lenses, direction for pedestrian traffic, on the straight sides of the signal, which face away from the line of motor traflic.

I claim:

1. A trafl'lc signal including a casing of a general triangular form, the major portion of one side including a plurality of curved lenses of predetermined colors, the casing divided horizontally into as many compartments as there are different colors of lenses, reflecting means for each compartment so placed and curved as to reflect light rays through opposed curved lenses, approximately perpendicular to the lenses at all points, and illuminating means located in the several compartments at a point between the curved lenses and the reflecting means.

2. A traffic signal including a casing of a general triangular form, the major portion of one side including a plurality of curved lenses of predetermined colors, the other two sides of the casing having a plurality of openings with lenses of predetermined colors, the casing divided horizontally into as many compartments as there are difierent colors of lenses, reflecting means for each compartment so placed and curved as to reflect light rays through opposed curved lenses, approximately perpendicular to the lenses at all points, the inner ends of the reflecting means leaving an opening therebetween, and illuminating means located in the several compartments in proximity to the opening between the curved reflecting means, through which the light rays extend from the illuminating means through the lenses in the said two sides.

3. A traflic signal including a casing of a general triangular form, the major portion of one side including a plurality of curved lenses of predetermined colors, the casing divided horizontally into as many compartments as there are diflerent colors of lenses, reflecting means for each compartment so placed and curved as to reflect light rays through opposed curved lenses, approximately perpendicular to the lenses at all points, illuminating means located in the several compartments at a point between the curved lenses and the reflecting means, and means extending outwardly from a point approximately at the inner ends of the curved lenses to shield the rays of light from one side of said shielding means from the rays of light on the opposite side thereof.

4. A combined traflic and pedestrian signal which includes an outer casing of three sides, one of which is composed mainly of a plurality of curved lenses of predetermined color and arrangement and the other two sides at an angle to each other and having a plurality of lenses of predetermined color and location, reflecting means extending approximately from the opposite corners of the casing, with an opening between their inner ends, said reflecting means curved in an opposite direction from the curvature of the lenses composing the one side of the casing and of a less degree of curvature in order to reflect light rays at the required angle through the said lenses, lenses in the two sides, a cloverleaf structure in the space between the reflecting means and the two sides of the casing and surrounding the lenses in said sides, said lenses of predetermined color and location, and illuminating means adjacent the opening between the curved reflecting means, the rays of light from which extend simultaneously through lenses on all sides of the casing.

5. A combined traflic and pedestrian signal which includes a casing having two sides at an angle to each other and a plurality of curved lenses of predetermined color and location extending from the outer edges of said two sides to an approximately central point and constituting a third side of the casing, curved reflecting means extending from the outer ends of the two sides to an approximately central point leaving an opening between their inner ends and of a curvature less than the curvature of the lenses whereby to reflect the light rays through the lenses in the lane of vehicular traflic, the other two sides of the container having openings 0pposite the opening between the reflecting means, lenses in said openings in the sides of predetermined color and location, and illuminating means so located and arranged within the casing with respect to the reflectors and open space therebetween that the rays of light therefrom extend through the several lenses THEODORE O. WOI-ILSEN. 

